Modified polynucleotides. IV. Template activity of 5-alkyluracil-containing poly [d(A-r5U)] copolymers for DNA and RNA polymerases.

The change of templating properties for E. coli DNA and RNA polymerases of poly[d(A-r5U)] copolymers on substitution of the uracil for 5-methyl-, 5-ethyl-, 5-n-propyl-, 5-n-butyl- or 5-n-pentyluracil, resp., was studied. All modified polymers proved to be more effective template-primers than poly[d(A-U)] or poly[d(A-T)] for the DNA polymerase. Direct dependence of the template-primer efficiency (vmax/Km) value on the thermal stability of the polymers was observed. For transcription the r = ethyl and n-propyl polymers were also more effective templates than poly[d(A-T)].